The present disclosure relates generally to tunable magnetoelectric inductors with large inductance tunability and a method of manufacturing such inductors. The invention also relates to semiconductor devices containing tunable magnetoelectric inductors.
Incorporating tunability in conventional RF front-end components allows for the development of radio architectures capable of operating over multiple bands and standards, resulting in a reduction in cost, size, complexity, and power consumption of the radio transceiver. Front-end components such as tunable filters, phase shifters, voltage controlled oscillators, tunable low-noise amplifiers, and other RF components use on-chip and off-chip passive electronic components. Inductors, as one of the three fundamental components for electronic circuits, are extensively used in these front-end components as well as in other electronic applications. Tunable inductors, especially tunable inductors suitable for use in RF circuits, are key elements in creating intelligent, reconfigurable radios. While electronically tunable capacitors and resistors have been widely used for such tasks, electronically tunable inductors have not been readily available, despite the broad range of uses for such inductors.
Different technologies have been explored for tunable RF inductors, including inductors with magnetic materials where the permeability can be tuned by a magnetic field, inductors with magnetic materials where the permeability can be tuned by changing the coupling of the inductor coil and the magnetic core, inductors where the winding is digitally controlled via MEMS switches, mechanical tuning of mutual inductance between coupled inductors, varactor-based tunable inductors created by connecting a varactor with a fixed inductor so as to vary the bias voltage applied across the varactor and thus tuning the effective inductance, and manually tuned inductors. Each of these tunable inductor technologies has shortcomings that prevent general and widespread acceptance. Magnetic field tuning requires significant power and a constant current. Mechanical tuning requires large, complex actuators which are difficult to fabricate. Switchable inductors are limited by the number of switches used and the number of switches is limited as increasing this number reduces inductor quality. Varactor-tuned inductors have low quality factors and limited tunability. Manually tuned inductors are inconvenient to use. These negative aspects to currently available tunable inductors limit their usage.